1. Field of the Invention
The present invention relates to open-end wrenches and specifically to the construction of the wrenching head of such a wrench.
2. Description of the Prior Art
A typical open-end wrench consists of an elongated handle shank and a wrenching head on either or both ends thereof, the head including two jaws, respectively provided with smooth planar driving surfaces that engage opposite sides of a polygonal fastener.
A disadvantage of such wrenches has been the inadequate gripping force between the driving surfaces and the fastener. As a result, the wrench has a tendency to slip off the fastener when torque is applied thereto. Also, it tends to deform and spread the wrench jaws and round and/or crush the fastener corners.
In copending U.S. application Ser. No. 487,921, filed Mar. 5, 1990, there is disclosed an open-end wrench which provides serrated regions on the driving surfaces to increase the gripping force.
However, that wrench still has relatively large jaws, with substantial jaw width, i.e., the dimension between the driving surface and the outer surface of the jaw, and jaw length. More specifically, the jaws are long enough to accommodate both square and hexagonal fasteners. This large jaw size limits the accessibility of the wrench to fasteners located in tight quarters.